Wear-resisting chrome-iron member



'Patented Dec. 19 24.

narily subjected.

" UNITED STATES rAT Nrfo 1 -,5 17,392 FF ICE.

rarmnmcx'm. Bnckm, or NEW YORK, n. Y., nssrenontro nrnc'rnomnrnnnuaercnn comrnm'r, on NEW YORK, n.1, A conronn'rron or wns'r vmemm.

wEan-n'nsrsrme CHROME-IRON MEMBER.

No Drawing.

To all'whom it may concern:

Be it known that I FREDERICK M. BECKET, a citizen of the flnited States,residing at New Yorkin the county of New York and State of llew York,have invented certain new and useful Improvements in Wear-ResistingChrome-Iron Members, of

which the followin is a specification.

This invention re ates to the manufacture from chrome-iron alloys ofmembers characterized by high surface hardness together with resistanceto corrosion, oxidation at elevated temperatures, and attack bycorrosive vapors or liquids. Such .members as are comprised within myinvention are sufliciently non-brittle, strong, and homogeneous to adaptthem to stand the strains and im-' members are ordi pacts to whichwearing United States me. on Nov. 6, 1917, discloses chrome-iron alloyscontaining 1.5% to 3% of carbon,

which are exceedingly hard and tough, andv resistant to oxidation evenat very high temperatures. These properties adapt'them corrosiveconditions, but the workability of, the compositions'in question is notsufliciently good to permit the ready shaping ofthealloy into thedesired form.

In the application filed by the present lagpplicantf and Charles E.McQuigg' on arch 3, 1922, Serial No. 540,885, non-corroding chrome-ironcompositions having a much better workability when heat-treated in themanner set forth therein, are dis closed. N The shaping of membersfromthe I compositions disclosed in said application is quite readilyaccompished, but a higher carbon content is often necessary to developthe maximum hardness and wear-resisting qualities possible for theproportions of iron and chromium present.

In accordance with the present invention' it is possible to produce analloy adapted by-its chromium content to resist corrosionandby itscarbon content for easy working, to shape the alloy into the desiredform, and then to increase the carbon content to such a figure that thedesired hard ness and resistance to wear are developed.

. It will usually be suflicient to increase the carbon content only Isuperficially-, giving a case or 'surfacelayer-of great '-'ha1fdness.-This obj act is attained: by subjecting. *the Patent1,245,552, issued toonly with difliculty.

Application filed September 7, 1922. ,SeriaI No. 586,783.

shaped member to a suitable carbonizin treatment. The. followingexamples wil serve to .illustrage the carbonizing opera-.

tion. I

A section. of sheet one-sixteenth inch .thick, containing 26.60%chromium, 0.80%-

carbon, 0.10% silicon and 0.39% manganese,

the remainder being iron, was packed in a commercial carbonizingmaterial of un-' for 108 hours. lVith this thin material, the

entire cross section became carbonized,

though doubtless to a varying degree, and a sample representing theentire jcross section showed a carbon content of 1.41%. The scleroscopichardness was 'r'naterially increased after carbonizatiori.

Another sample having a cross section which roughly resembled a righttriangle with a base of about 0.65 inch and an altitude of about 0.5inch, was heated in the same material at 960 C. for 48 hours. Theinitials-composition of the alloy was: chromium 28.77%, carbon 1.25%,silicon 1.29%

and manganese 0.65%, the remainder being iron. After carboni'zat-ion,the average carbon content of the entlre cross section was 1.73%, whilea sample of metal taken from the surface contained 1.92% carbon. The

surface hardness of this sample was also increased. V

The carboniz ing compound employed in the specific examples is onecommonly used for the hardening of ordinary steels and is regarded as avery'active carbonizing material. It is believed thatthe carbonizingmaterials now in use for, hardening steels are in general alsoapplicable to chromium alloys.

The finishedrmember, its size and the ,carb'onizing treatment are suchthat carbonizatio'n-hasnot proceeded to the center, may-have an interiorportlon of a composl- .tio'n corresponding to a readily workablematerial. However, the invention also comprises members such as maresult from the carbonization of pieces w 'ch even before such treatmenthad a carbon content so high that they could not be'rolled or drawn, or

'Members of the have man applicationsbut are particularly suitable orthe wearing parts of gauges,-

kind described hereinj and for bearings, especially the balls and racesof ball bearings. When the chromium content is upward of 20%, they maybe subjected to high temperatures and to cor-' rosive conditions withoutlosing their usefulness.

I claim: 4 i

1. A member which in its regular use is continually subjected toabrasion, composed 10 of case-carbonized chrome-iron.

2. A member which in its regular use is continually subjected toabrasion, composed of casc-carbonized chrome-iron of suflicient chromiumcontent to render it 15 non-corroding.

3. A member which in its regular use is continually subjecfod toabrasion, composed of case-carbonized chromcdron containing upward of20% of chromium. j

4. A ball-bearing member composed of case-carbonized chrome-iron.

5. A ball-bearing member composed of case-carbonized chrome-iron ofsufficient chromium content to render it, non-corrod- 6. Acase-carbonized ball-bearing member containing upward of 20% chromium.

In testimony whereof, I affix my signature. FREDERICK M. BECKET.

